[Intel-gfx] [PATCH] drm/i915/gvt: Implement WaForceWakeRenderDuringMmioTLBInvalidate

[Arkadiusz Hiler]

When invalidating RCS TLB the device can enter RC6 state interrupting
the process, therefore the need for render forcewake for the whole
procedure.

This WA is needed for all production SKL SKUs.

References: HSD#2136899, HSD#1404391274
Cc: Mika Kuoppala <mika.kuoppala at intel.com>
Cc: Zhenyu Wang <zhenyuw at linux.intel.com>
Signed-off-by: Arkadiusz Hiler <arkadiusz.hiler at intel.com>
---
 drivers/gpu/drm/i915/gvt/render.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/i915/gvt/render.c b/drivers/gpu/drm/i915/gvt/render.c
index f54ab85..f5000ea 100644
--- a/drivers/gpu/drm/i915/gvt/render.c
+++ b/drivers/gpu/drm/i915/gvt/render.c
@@ -134,11 +134,22 @@ static void handle_tlb_pending_event(struct intel_vgpu *vgpu, int ring_id)
 
 	reg = _MMIO(regs[ring_id]);
 
+	/* WaForceWakeRenderDuringMmioTLBInvalidate:skl
+	 * we need to put a forcewake when invalidating RCS TLB caches,
+	 * otherwise device can go to RC6 state and interrupt invalidation
+	 * process */
+	if (IS_SKYLAKE(dev_priv) && ring_id == RCS)
+		intel_uncore_forcewake_get(dev_priv, FORCEWAKE_RENDER);
+
 	I915_WRITE(reg, 0x1);
 
 	if (wait_for_atomic((I915_READ(reg) == 0), 50))
 		gvt_err("timeout in invalidate ring (%d) tlb\n", ring_id);
 
+	if (IS_SKYLAKE(dev_priv) && ring_id == RCS)
+		intel_uncore_forcewake_put(dev_priv, FORCEWAKE_RENDER);
+
+
 	gvt_dbg_core("invalidate TLB for ring %d\n", ring_id);
 }
 
-- 
2.7.4